Note: while I'm no longer maintaining Ookii.Dialogs, some awesome people on GitHub have forked the project and are keeping it up to date.
Ookii.Dialogs is a class library for .Net applications providing several common dialogs. Included are classes for task dialogs, credential dialogs, progress dialogs, input dialogs, and common file dialogs.
This package contains two class libraries: Ookii.Dialogs.dll for use with Windows Forms, and Ookii.Dialogs.Wpf.dll for use with Windows Presentation Foundation. The classes inside are pretty much identical; only the input dialog is not available for WPF. Some additional utility classes for Windows Forms are provided that are not available for WPF, see below for details.
The included sample applications Ookii.Dialogs.Sample.exe and Ookii.Dialogs.Sample.Wpf.exe demonstrate the dialogs for Windows Forms and WPF respectively. View the source of these applications to see how to use the dialogs.
Task dialogs are a new type of dialog first introduced in Windows Vista. They provide a superset of the message box functionality.
The Ookii.Dialogs.TaskDialog (for Windows Forms) and the Ookii.Dialogs.Wpf.TaskDialog (for WPF) classes provide access to the task dialog functionality. The TaskDialog class inherits from System.ComponentModel.Component and offers full support for the Windows Forms designer and component designer of Visual Studio 2008.
The TaskDialog class requires Windows Vista or a later version of Windows. Windows XP is not supported. Note that it is safe to instantiate the TaskDialog class and set any of its properties; only when the dialog is shown will a NotSupportedException be thrown on unsupported operating systems.
Progress dialogs are a common dialog to show progress during operations that may take a long time. They are used extensively in the Windows shell, and an API has been available since Windows 2000.
The Ookii.Dialogs.ProgressDialog (for Windows Forms) and the Ookii.Dialogs.Wpf.ProgressDialog (for WPF) classes provide a wrapper for the Windows progress dialog API. The ProgressDialog class inherits from System.ComponentModel.Component and offers full support for the Windows Forms designer and component designer of Visual Studio 2008. The ProgressDialog class resembles the System.ComponentModel.BackgroundWorker class and can be used in much the same way as that class.
The progress dialog's behaviour of the ShowDialog function is slightly different than that of other .Net dialogs; please read the reference documentation for more information. It is recommended to use a non-modal dialog with the Show function.
The ProgressDialog class is supported on Windows XP and later versions of Windows. However, the progress dialog has a very different appearance on Windows Vista and later (the image above shows the Vista version), so it is recommended to test on both operating systems to see if it appears to your satisfaction.
When using Windows 7, the ProgressDialog class automatically provides progress notification in the application's task bar button.
The Ookii.Dialogs.CredentialDialog (for Windows Forms) and the Ookii.Dialogs.Wpf.CredentialDialog (for WPF) classes provide wrappers for the CredUI functionality first introduced in Windows XP. This class provides functionality for saving and retrieving generic credentials, as well as displaying the credential UI dialog. This class does not support all functionality of CredUI; only generic credentials are supported, thing such as domain credentials or alternative authentication providers (e.g. smart cards or biometric devices) are not supported.
The CredentialDialog class inherits from System.ComponentModel.Component and offers full support for the Windows Forms designer and component designer of Visual Studio 2008.
On Windows XP, the CredentialDialog class will use the CredUIPromptForCredentials function to show the dialog; on Windows Vista and later, the CredUIPromptForWindowsCredentials function is used instead to show the new dialog introduced with Windows Vista. Because of the difference in appearance in the two versions (the image above shows the Vista version), it is recommended to test on both operating systems to see if it appears to your satisfaction.
The input dialog is a dialog that can be used to prompt the user for a single piece of text. Its functionality is reminiscent of the Visual Basic InputBox function, only with a cleaner API and UI.
The Ookii.Dialogs.InputDialog class provides the input dialog functionality for Windows Forms. This class is not available for WPF.
Unlike the other classes in this package, this class is not a wrapper for any existing API; the dialog uses a custom implementation in Windows Forms. This dialog is supported on Windows XP and later versions of windows; on Windows Vista and later, the visual styles API is used to draw the dialog to mimic the appearance of task dialogs, as shown in the image above.
The InputDialog class inherits from System.ComponentModel.Component and offers full support for the Windows Forms designer and component designer of Visual Studio 2008.
Windows Vista introduced a new style of common file dialogs. As of .Net 3.5 SP1, the Windows Forms OpenFileDialog and SaveFileDialog class will automatically use the new style under most circumstances; however, some settings (such as setting ShowReadOnly to true) still cause it to revert to the old dialog. The FolderBrowserDialog still uses the old style. In WPF, the Microsoft.Win32.OpenFileDialog and SaveFileDialog classes still use the old style dialogs, and a folder browser dialog is not provided at all.
The Ookii.Dialogs.VistaOpenFileDialog, Ookii.Dialogs.VistaSaveFileDialog and Ookii.Dialogs.VistaFolderBrowserDialog provide these dialogs for Windows Forms (note that in the case of the OpenFileDialog and SaveFileDialog it is recommended to use the built-in .Net classes unless you hit one of the scenarios where those classes use the old dialogs). The Ookii.Dialogs.Wpf.VistaOpenFileDialog, Ookii.Dialogs.Wpf.VistaSaveFileDialog and Ookii.Dialogs.Wpf.VistaFolderBrowserDialog classes provide the same functionality for WPF.
The classes have been designed to resemble the original Windows Forms and WPF classes to make it easy to switch. When the classes are used on Windows XP, they will automatically fall back to the old style dialog; this is also true for the VistaFolderBrowserDialog on WPF; that class provides a complete implementation of a folder browser dialog for WPF, old as well as new style.
The Vista-style file and folder dialogs classes for Windows Forms inherit from System.ComponentModel.Component and offer full support for the Windows Forms designer and component designer of Visual Studio 2008.
Three additional classes are provided for Windows Forms only, in the Ookii.Dialogs library. These classes are used to support the InputDialog (with the exception of the Aero glass functionality, which the InputDialog does not use) but are made public for your convenience.
The AdditionalVisualStyleElements class provides some visual style elements used by task dialogs on Windows Vista and later.
The Glass class provides functionality for extending Aero glass into the client area of a window on Windows Vista and later, and for drawing text on a glass surface.
The ExtendedForm class serves as an alternative base class for forms, and provides functionality to automatically use the system font (e.g. Tahoma on XP and Segoe UI on Vista and later), and easy access to some of the functionality of the Glass class.